A school has two sections of a math class. Section 1 has 30 students with an average score of 70. Section 2 has 20 students with an average score of 90. When the scores of both sections are combined, which of the following statements about the overall average score is true?
The overall average will be exactly 80.
The overall average will be less than 80.
The overall average will be greater than 80.
The overall average cannot be determined without knowing individual scores.
